Acoustical horn



. J. POLYDOROFF AcoUsTIcAL HORN Filed June 21. 1928 2 Sheets-Sheet l Jfzggt A TTORNEX June 24, 1930 June 24, 1930. w. .J; PoLYDQRol-F 1,767,812

ACOUSTICAL HORN Filed June 2l. 1928 2 Sheets-Sheet 2 wm a ggg/212% www e m m,

ATTORNEY Patented June 24, 1930 UNITED STATES PATENT OFFICE WI-ADIMIR J. POLYDOROFF, OF CHICAGO, ILLINOIS, ASSIGNOR TO JOHNSON LABOBA; TORIES, INC., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS ACOUSTICAL HORN Application led Jun v21, 1928. Serial No. 287,053.

The invention relates to acoustical horns, an object thereof being to produce a horn having not only desirable acoustical properties, but an air passage of maximum length within its cubical dimensions. A further object of the invention is to produce a horn which is easily and cheaply produced and is inherently strong and, therefore, capable of withstanding shocks incident to shipping and handling.

The body of a horn made in accordance with said invention, includes a continuous winding sound channel having a flared terminal portion constituting the mouth of the horn, and said body is, preferabl made in matched disks or sections Whic may be independentl molded, machined or die pressed, and then glued, cemented or fastened together in any suitable way.k These matched disks or sections may be three in number, although it is' possible to embody the invention in a horn having a dilferent number of parts.

The invention will be best understood if reference'be had to the accompanying drawing in which:

Fig. 1 is a perspective view of a horn embodylng said invention;

Fig. 2 is a view in elevation showing the sections, the winding passages of the horn being delineated by dotted lines;

Fig. 3 is a. plan view of the open section of the horn, Fig. 3-A being its cross-section on the line 3-A, Fig. 3;

Fig. 4 is a plan view showing one side of the intermediate section of said horn, Fig. 4-A being its cross-section on the line 4-A, Fig. 4;

Fig. 5 is a plan view of the closed section of the horn, Fig. 5-A being its cross-section The horn, if made in three parts, has an open section 1, a closed section 2, and an intermediate section 3.

The open section l has a central flared opening 4, and its posterior flat surface is provided with a tapering groove 5, the smaller end of said groove being indicated by the numeral 6, and the larger end thereof being indicated by the numeral 7 The proximate flat surface 4of the intermediate section 3, is provided with a groove 8, this groove being a replica of said groove 5, whereby the two grooves ma cooperate to form a portion of the tapere sound channel. Said intermediate section is also provided with a tapered opening 9, the larger end of which matches the smaller end of the tapered opening 4 in said section 1.

The abutting surfaces of the closed section 2 and said intermediate section 3 are, respectively, provided with mating grooves 10 and 11, which together may form a portion of the sound channel of the horn.

The intermediate section 3 is provided with a port 12 which establishes communication between the air channels of the three sections.

The respective mating grooves being entirely outsideof the sections of the horn are readily formed by molding or otherwise. Diicult internal work is, therefore, avoided.

The sections of the horn may be as numerous as desired, and may be formed of plastic material, metal or other material.

The invention provides for aconsiderable length of the sound channel relatively to the outside dimensions of the horn. A horn constructed as herein described, having an outside cylindrical form, and having a diameter of 13 inches and a height of 7 inches was built, and this horn has a sound 1channel which is approximately 60 ,inches ong.

It will be observed that the smaller end of* the sound passage of the `horn is proximate the larger end of the opening of said horn, and that the larger end of said sound passage is proximate the smaller end' of said opening, the relations of these features of the horn being therefore such that Said horn has minimum external lateral` dimensions, thus making it possible to use a small quantity of material in the manufacture of` said horn.

The several sections constituting the horn may be enclosed in a casing having a body portion 17, "and a removable front 18 of cloth or other material secured to said body portion b suitable means, such as the screw threads s own in Figure 2.

Having thus described my invention, what I claim is:

l. A horn having mating grooved sections forming sound channels, said channels being united by a port extending through one of said sections.

.2. A horn comprising a plurality of sections, an intermediate section of said horn having grooves on faces thereof constituting parts of the sound channel of said horn, and said intermediate section having an opening extending from one to the other of l5 said grooves. u

3. A horn comprlsingaplural-lty of united disc sections each having a groove mating with the groove of an adjacent section, said grooves forming a substantially helical sound passage.

4. A horn comprising a plurality of united disc sections each having a groove matin with the groove of an adjacent section, sai grooves forming a substantially helical and' gradually enlarged sound passage, and said horn having also a flared mouth originating at the large end of and extending'through said horn.

5. A horn having a substantially helical sound passage therein, and formed of sections arranged side by side and in which sequential parts of said sound-passage are included, one of said sections being di'sposed intermediate other sections of said horn.

6. A sectional horn having a flared mouth and a plurality of communicating helical passages formed by mating grooves in the respective sections of said horn and dis 40 posed. in diierent planes around said flared Y mouth.

7. A sectional .horn having 'a mouth and substantially lhelical passages surrounding and leading to said mouth, the sections of said horn having abutting faces and being disposed at substantially right angles to the axis of said horn. Y

In testimony whereof I alix my signature WLAnImR J. PoLYDoRoFF. 

